Layer-by-Layer Assembly: An Emerging, Tailored and Robust Platform for Solar Water Splitting

Abstract

Photoelectrochemical (PEC) water splitting represents a highly promising technology to convert solar energy into clean and renewable chemical fuels. Among the divergent strategies utilized for customizing photoelectrodes, layer-by-layer (LbL) assembly has emerged as a green, simple, and easily accessible technique for rationally constructing multilayered heterostructures in terms of versatility, flexibility, and atomic-level exquisite interface configuration modulation. However, precise design of robust photoelectrodes based on LbL assembly still remains in the exploratory stage. This review comprehensively summaries the recent advancements in the fabrication of composite multilayer photoanodes via LbL assembly, highlighting the LbL assembly buildup with diverse substrates (e.g., metal oxides, transition metal sulfides) and building blocks of varying size and dimension (e.g., quantum dots, nanoclusters, nanoparticles, nanosheets). Furthermore, we underscore the role of these building blocks in extending the light absorption and improving the solar water oxidation performances. Most importantly, the latest endeavors devoted to mediating directional charge transfer route in artificial PEC systems are specifically summarized. Finally, prospects and challenges of LbL assembly technology in photoelectrode engineering for PEC water splitting are envisioned, aiming to inspire innovative strategies for the smart design of composite nanostructured photoelectrodes towards solar energy conversion.